A variety of systems and techniques are known for combining integrated circuits in compact modules. Some techniques are suitable for combining packaged integrated circuits while other techniques are suitable for combining semiconductor die. Many systems and techniques employ flex circuitry as a connector between packaged integrated circuits in, for example, stacks of packaged leaded or chip-scale integrated circuits. Other techniques employ flex circuitry to “package” semiconductor die and function as a substitute for packaging.
Within the group of technologies that stack packaged integrated circuits, some techniques are devised for stacking chip-scale packaged devices (CSPs) while other systems and methods are better directed to leaded packages such as those that exhibit a set of leads extending from at least one lateral side of a typically rectangular package.
Integrated circuit devices (ICs) are packaged in both chip-scale (CSP) and leaded packages. However, techniques for stacking CSP devices are typically not optimum for stacking leaded devices, just as techniques for leaded device stacking are typically not suitable for CSP devices. Few technologies are, however, directed toward combining packaged integrated circuits with semiconductor die.
Although CSP devices are gaining market share, in many areas, integrated circuits continue to be packaged in high volumes in leaded packages. For example, the well-known flash memory integrated circuit is typically packaged in a leaded package with fine-pitched leads emergent from one or both sides of the package. A common package for flash memory is the thin small outline package commonly known as the TSOP typified by leads emergent from one or more (typically a pair of opposite sides) lateral sides of the package.
Flash memory devices are gaining wide use in a variety of applications. Typically employed with a controller for protocol adaption, flash memory is employed in solid state memory storage applications that are supplanting disk drive technologies. However, when flash memory is employed with controller logic, the application footprint typically expands to accommodate the multiple devices required to provide a module that is readily compatible with most memory subsystem interface requirements. Consequently, what is needed is a memory module that includes a controller logic and flash memory storage without substantial increases in footprint or thickness.